IPVS: ftp: loaded support on port[0] = 21 IPVS: ftp: loaded support on port[0] = 21 IPVS: sync thread started: state = BACKUP, mcast_ifn = lo, syncid = 0, id = 0 ============================================ WARNING: possible recursive locking detected 4.16.0-rc7+ #370 Not tainted -------------------------------------------- syz-executor0/4450 is trying to acquire lock: (rtnl_mutex){+.+.}, at: [<0000000014a7a2fd>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74 but task is already holding lock: (rtnl_mutex){+.+.}, at: [<0000000014a7a2fd>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(rtnl_mutex); lock(rtnl_mutex); *** DEADLOCK *** May be due to missing lock nesting notation 2 locks held by syz-executor0/4450: #0: (rtnl_mutex){+.+.}, at: [<0000000014a7a2fd>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74 #1: (ipvs->sync_mutex){+.+.}, at: [<00000000fe83a639>] do_ip_vs_set_ctl+0x10f8/0x1cc0 net/netfilter/ipvs/ip_vs_ctl.c:2388 stack backtrace: CPU: 0 PID: 4450 Comm: syz-executor0 Not tainted 4.16.0-rc7+ #370 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x24d lib/dump_stack.c:53 print_deadlock_bug kernel/locking/lockdep.c:1761 [inline] check_deadlock kernel/locking/lockdep.c:1805 [inline] validate_chain kernel/locking/lockdep.c:2401 [inline] __lock_acquire+0xe8f/0x3e00 kernel/locking/lockdep.c:3431 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:3920 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74 ip_mc_drop_socket+0x88/0x230 net/ipv4/igmp.c:2643 inet_release+0x4e/0x1c0 net/ipv4/af_inet.c:413 sock_release+0x8d/0x1e0 net/socket.c:595 start_sync_thread+0x2213/0x2b70 net/netfilter/ipvs/ip_vs_sync.c:1924 do_ip_vs_set_ctl+0x1139/0x1cc0 net/netfilter/ipvs/ip_vs_ctl.c:2389 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline] nf_setsockopt+0x67/0xc0 net/netfilter/nf_sockopt.c:115 ip_setsockopt+0x97/0xa0 net/ipv4/ip_sockglue.c:1261 udp_setsockopt+0x45/0x80 net/ipv4/udp.c:2406 ipv6_setsockopt+0xa0/0x130 net/ipv6/ipv6_sockglue.c:917 udpv6_setsockopt+0x45/0x80 net/ipv6/udp.c:1422 sock_common_setsockopt+0x95/0xd0 net/core/sock.c:2975 SYSC_setsockopt net/socket.c:1849 [inline] SyS_setsockopt+0x189/0x360 net/socket.c:1828 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x4548b9 RSP: 002b:00007fd65baf3c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 00007fd65baf46d4 RCX: 00000000004548b9 RDX: 000000000000048b RSI: 0000000000000000 RDI: 0000000000000008 RBP: 000000000072bea0 R08: 0000000000000018 R09: 0000000000000000 R10: 0000000020000100 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000051b R14: 00000000006f9b28 R15: 0000000000000000